1. Field of the Invention
The present invention relates to an exposure apparatus and a laser working method in which an object to be exposed is irradiated with light through a mask capable of dynamically controlling pattern.
It also relates to a fine working method for a complex material and a complex shape, such as a micromachine, an IC or a hybrid IC device.
2. Related Background Art
Conventionally, the mask used for projecting a light pattern onto an object to be exposed has been composed of a metal plate in which a pattern is formed by electroforming or a glass plate such as of quartz on which a metal film such as of chromium is patterned.
However, such conventional pattern, being composed of a fixed mask or mask pattern which is static and unchangeable, has a limitation in the range of pattern projection depending on the limitation in size of the mask or of the optical system used for projecting the mask pattern. For example, with a mask of 8 inches square and an absolute projecting magnification of ⅕, there can only be exposed an area of about 40 mm square by the projection of the pattern of the entire mask.
Also in case of a projecting magnification of 1/1, there can be exposed an area of 8 inches square at maximum, the precision of the mask pattern itself is directly projected and cannot, therefore, be improved on the projected image. This is because, in case of reduction projection, the precision of the pattern of the projected image is improved according to the projection magnification. Also, an exposure area of 8 inches square need not necessarily be sufficiently large.
In consideration of the foregoing, the object of the present invention is to provide an exposure apparatus and a laser working method capable of executing exposure on a large area, without limitation in the area of pattern projection by the size of the mask or of the optical system used for projection the mask pattern.
The above-mentioned object can be attained, according to the present invention, by an exposure apparatus and a laser working method constructed as in the following configurations (1) to (16):
(1) An exposure apparatus for exposing an object of exposure to a pattern of a mask by reduction projection with a projection lens utilizing light from a light source, comprising a mask fixed to the optical axis, means for dynamically moving the pattern and means for moving the object of exposure, wherein the exposure is executed while the object of exposure is moved in synchronization with the movement of the pattern displayed by the mask.
(2) An exposure apparatus according to (1), wherein the means for moving the object of exposure is means for moving the object of exposure in a plane perpendicular to the optical axis in synchronization with the movement of the pattern displayed by the mask.
(3) An exposure apparatus according to (1), wherein the means for dynamically moving the pattern of the mask is a light transmitting mask composed of a liquid crystal device capable of dynamically controlling the pattern.
(4) An exposure apparatus according to (1), wherein the light from the light source is linearly polarized light, and the polarizing filter employed in the liquid crystal device is composed only of a single light emitting polarizing filter perpendicular or parallel to the polarizing direction of the incident light, according to the setting of negative or positive transmission.
(5) An exposure apparatus according to (1), wherein the light from the light source is laser light from a laser oscillator which executes continuous emission of light pulses of a large energy density in space and time, with a pulse emission time not exceeding 1 picosecond.
(6) An exposure apparatus according to (5), wherein the laser oscillator is provided with a space compression device for the light propagation.
(7) An exposure apparatus according to (1) or (6), wherein the space compression device for the light propagation includes means for generating a chirped pulse and vertical mode synchronization means utilizing light wavelength dispersion characteristics.
(8) A laser working method for working an object of working by reduction projection of a pattern of a mask by a projection lens utilizing light from a laser oscillator, which comprises utilizing a mask fixed to the optical axis, dynamically moving the pattern and working the object of working while the object of working is moved in synchronization with the movement of the pattern displayed by the mask.
(9) A laser working method according to (8), wherein the object of working is worked while the object of working is moved in a plane perpendicular to the optical axis in synchronization with the movement of the pattern displayed by the mask.
(10) A laser working method according to (8), wherein the mask is a light transmitting mask composed of a liquid crystal device capable of dynamically controlling the pattern.
(11) A laser working method according to (8), wherein the laser light entering the mask is linearly polarized light, and the polarizing filter employed in the liquid crystal device is composed only of a single light emitting polarizing filter perpendicular or parallel to the polarizing direction of the incident light, according to the setting of negative or positive transmission.
(12) A laser working method according to (8), wherein the projection magnification of the projection lens projecting the mask does not exceed {fraction (1/20)} in the absolute value.
(13) A laser working method according to (8), wherein the position of the mask or the object of working is so changed, in synchronization of the progress of working of the object of working, that the focus point of the pattern image of the projected mask is on a position of working in the direction of the optical axis.
(14) A laser working method according to (8), wherein the light from the laser oscillator is laser light from a laser oscillator which executes continuous emission of light pulses of a large energy density in space and time, with a pulse emission time not exceeding 1 picosecond.
(15) A laser working method according to (14), wherein the laser oscillator is provided with a space compression device for the light propagation.
(16) A laser working method according to (14), wherein the space compression device for the light propagation includes means for generating a chirped pulse and vertical mode synchronization means utilizing light wavelength dispersion characteristics.